Smart-phone Screencast to Airline Seat-back Screens?

If the ban on electronic devices larger than a cellphone in aircraft cabins continues, it may be worth airlines adding smart-phone interfaces to their seat-back screens. Many airlines already provide a USB socket which can be used to charge a phone, or access data on a flash drive. However the interface offered by the in-flight entertainment system for accessing the flash drive data tends to be slow and cumbersome. An alternative would be to screen-cast from the smart-phone to the seat-back display, via the USB cable (which would power the phone at the same time). The passenger would use their phone touch screen as the interface, and have access to the phone's data and applications, but see the results on the much bigger aircraft screen.